A little help understanding M.2 and PCIe lanes please?

[hagakure.s81]

Hi all,

 

I'm currently in the process of collecting parts for a new Skylake / Z170 based build.

I have already a Crucial MX-100 sata based SSD (512gb) that i'm going to keep from my previous computer as i didn't yet have it a very long time.

I wasn't planning on getting any M.2 NVMe / PCIe based SSD but during the Black Friday weekend i saw one from Toshiba/OCZ (RVD400-M22280-256G) on sale and got it.

Now i' haven't yet bought the motherboard, CPU or GPU.

 

My question relates to the PCIe lanes and how it is set up on the motherboard.

I've been planning to get the Asus Z170-A motherboard (actually likely the Z170-AR since for some reason only that version is available in New Zealand, but there doesn't seem to be much difference between them). The motherboard does have a dedicated M.2 slot (4 x 3.0 I believe)

For reference, CPU will be a 6600k (perhaps a 6700k) and a single GTX 1070 (probably EVGA SC Gaming) as the GPU.

 

What I can't seem to find, or sort thru the technical jargon; is whether the M.2 card will take away PCIe lanes from the graphics card, or whether it has its own dedicated lanes.

And if it does, will there be a noticeable drop in performance of the GTX 1070 in 8x rather than 16x? What about if the graphics card / system is running in overclocked or boost mode?

Are there Z170 motherboards you would recommend instead of the Z170-AR if the above are true?

[Electronics Wizardy]

2 minutes ago, Panopticon_81 said:

M.2 card will take away PCIe lanes from the graphics card,

The m.2 uses lanes from the chipset.

 

WIth z170 you have anouther 20 pcie lanes from the chipset for ssd's nics, raid cards, usb, thunderbolt and other things. All 16 cpus lanes will be used fort the gpu.

[Bananasplit_00]

your I5 6600K or I7 6700K will have enough PCIe lanes anyway, should be just fine

[hagakure.s81]

Right, thanks for that guys.

 

So do I understand you correctly that the Z170 motherboards have 20 PCIe lanes above and beyond the 16 used by the graphics cards?

I do remember that the SATA express lanes share some bandwidth but I don't think I'll be using those anyway.

 

In case you hadn't noticed yet i'm a noob at this btw  - I do try to read up and research before asking but in this case I couldn't get my head around it.

[hagakure.s81]

3 minutes ago, Thread212 said:

M.2 Use chipset lanes. Pci-e SSD use CPU lanes.

U dont have to worry about x8 will cut the performance in half as most graphic card cant saturate X8 Gen3.

CMIIW.

Ok thanks for your reply.

The SSD i got is the M.2 configuration - it does come with a PCIe card adaptor-thingee but since the motherboard I was planning on getting has a dedicated M.2 4 x 3.0 slot I wasn't planning to use the adaptor card.